The present invention relates to a resin composition suitable for providing coating layers on release papers or, more particularly, to a resin composition suitable for providing coating layers on in-process release papers used in the manufacturing process of, for example, synthetic leathers from polyurethane resins, polyvinyl chloride resins, polyamide resins, poly(amino acid) resins and the like by the method of casting or similar processes. The inventive resin composition not only satisfies general requirements for the in-process releasing agents but also gives in-process release papers having excellent peelability at elevated temperatures and surface gloss.
Hitherto known resin compositions used to impart releasability or peelability to the surface of papers used in various manufacturing processes are classified to polypropylene-based ones, aminoalkyd resin-based ones and silicone resin-based ones as the typical classes in current use. These prior art resin compositions, however, have their own defective points or problems.
For example, release papers prepared with a polypropylene-based resin composition withstand repeated use with highly durable peelability but their performance is limited in use at a relatively high temperature. When used at an elevated temperature, the surface of the release paper is apt to be marred and no strong gloss can be imparted to the surface of the products such as synthetic leathers.
On the other hand, aminoalkyd resin-based compositions are superior in respect of the surface gloss of products but rather inferior in their peelability while silicone resin-based ones have excellent peelability but poor gloss so that they are not suitable for the manufacture of synthetic leathers of high surface gloss.
Thus, it has been an important problem in the technology of release papers to develop a novel resin composition suitable for the preparation of in-process release papers having good releasability or peelability and durability in high temperature use and capable of producing synthetic leathers and other products with high surface gloss.